Discovery - no service - forget about the customer!

I changed bank accounts. On 09 Sep 2019 I send vitality a mail with my changed banking details (the ref no is ***). Today, 29 Oct 2019 my banking details have not been updated. (this after i followed up with at least 15 other reference numbers. I also lodged a complaint with ref no *** where I was promised feedback within 48 hours. Obviously this did not happened. 7 weeks to change a bank account - can a Corporate company be this useless - maybe they don't have funds!